Rasulullah (sallallahu’alayhi wasallam) ordered that a branch of a date palm be broken in 2 pieces and placed on the graves, after which he said;

‘Perhaps it will lighten the punishment for them (the 2 inmates) as long as these (branches) do not dry out’

(Sahih Bukhari, hadith: 216)

Because of the above, some Sahabah (radiyallahu’anhum) would bequest that after their burial, a date branch should be erected on their grave/placed in the grave. This has been reported from Sayyiduna Buraydah & Sayyiduna Abu Barzah (radiyallahu’anhuma)

The commentators mention: it is possible that the reason for this is because the fresh branch/ plant engages in the dhikr (remembrance) of Allah – like every other living thing- (Fathul Bari & Tafsir Ibn Kathir; Surah Isra, verse: 44)

Note: The above will be achieved with any type of branch or plant; it doesn’t have to be from the date palm or any one particular flower.